Condenser for condensing a refrigerant

ABSTRACT

A condenser for a compressor type refrigerating plant comprises a vessel traversed by at least one heat exchange tube and holds a body of liquid refrigerant into which the compressed vapor is injected to be condensed by a direct contact. The condensate thus obtained is further cooled before transferred into the evaporator.

United States Patent 1191 Andersson et al.

1451 Aug. 12, 1975 CONDENSER FOR CONDENSING A REFRIGERANT Inventors: Bror Gustav Andersson, Sodergatan 31; Benkt Reino Andersson, Rohdes vag, both of Varberg, Sweden Filed: Apr. 2, 1973 Appl. No.: 346,882

US. Cl. 62/507; 62/115; 261/153; 261/156 Int. Cl. F25b 39/04 Field of Search 62/115, 119, 121, 498, 62/506, 507, 509; 261/140, 140 A, 153, 156

References Cited UNlTED STATES PATENTS 4/1925 Pownall 62/509 X 7/1926 Hack 3/1920 Kucher 62/506 X 2,797,554 7 1957 Donovan 62/513 x 2,836,965 6/1958 Kleist 3,036,443 5/1962 Trepayd.... 3,403,314 9/1968 Maynard 62/183 ux FOREIGN PATENTS OR APPLICATIONS 549,359 1923 France 62/506 Primary Examiner-William F. ODea Assistant ExaminerPeter D. Ferguson Attorney, Agent, or FirmHolman & Stern 5 7 ABSTRACT 6 Claims, 4 Drawing Figures PATENTEU AUG 1 2 I975 SHEET PATENTEUAHB 1 21% 3,898,867

SHEET 3 PATENTEB AUG] 2 I975 FIG.4

CONDENSER FOR CONDENSING A REFRIGERANT BACKGROUND OF THE INVENTION The present invention refers to a method of condenstype including an evaporator, a compressor and a condenser connected in a closed circuit and also pertains to a condenser for performing such condensation.

With large refrigerating plants the condenser is usually cooled by water drawn from the domestic water supply. The thermal efficiency of such an arrangement is high, but the consumption of water may be considerable.

Many plants, and especially small and moderate sized ones, are therefore usually provided with air cooling, which however suffers from the grave disadvantage that it is dependent upon the ambient temperature, which brings about difficulties with respect to the governing of the temperature of the condensate. Only by using power consuming fans and a complicated governing system is it possible to reach satisfactory results at high installation, operating and maintenance costs.

The aim of the present invention is to propose a method for a rapid, direct condensation of the vaporized refrigerant so this becomes transferred into liquid state. As the heat transfer between a metal body and a liquid is to 6 times as high as between a metal body and a gas a more rapid reduction down to the desired temperature is obtained. A further object of the invention is to propose a condenser for bringing about the rapid direct condensation, and which without complicated governing means will maintain the desired temperature of the condensate, irrespective of variations in the ambient temperature.

SUMMARY OF THE INVENTION The method according to the invention is characterized in that the evaporated refrigerant leaving the compressor is introduced into a condenser formed as a vessel substantially filled with condensed refrigerant in such a manner that the vapor is forced to pass through a sufficient quantity of condensate to guarantee that the gas will be converted into liquid state, and that a quantity of condensate, corresponding to the quantity thus added after further cooling is transferred to the evaporator.

A condenser according to the invention is characterized in that it includes a vessel provided with at least one internal, hollow member forming a through passage for the cooling air, the vessel being provided with inlet means for the vaporized refrigerant and outlet means for the condensed refrigerant arranged in such a manner that the vessel will be substantially filled with condensate and the gas must pass a sufficient quantity of condensate to be transferred into liquid state.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows the basic arrangement of a refrigerating apparatus according to the invention;

FIG. 2 shows a section through a first embodiment of a condenser according to the invention;

FIG. 3 shows a section through a further embodiment of the condenser according to the invention; and

FIG. 4 shows a section view taken along the line ll II in FIG. 3.

DESCRIPTION OF SOME PREFERRED EMBODIMENTS The refrigerating apparatus very schematically shown in FIG. 1 comprises a cooling battery, or evaporator 50, in which the refrigerant is transferred from liquid state into vapor state, while absorbing heat from the surroundings, thus in reality cooling the same.

From the evaporator, the gas by way of a conduit 51 is conveyed to a compressor 52. The compressed vapor is conveyed away therefrom by means of a conduit 53 to a first step 54 in a heat exchanger/condenser. This first step is formed as a closed vessel, which is substantially filled with condensate and where the supply conduit 53 protrudes thus far into the vessel, that the vapor during its passage through the condensate will surely be transferred into liquid state.

A quantity of condensate corresponding to the freshly added quantity is continously withdrawn and transferred to the second step 56 of the heat exchanger/condenser. Here the condensate is cooled by giving away part ofits heat content to the surroundings, which occurs at high efficiency, as the transfer is from liquid to metal.

For a given capacity the combined contact surfaces of the vessel 54 and the second step 56 will be less the contact surface of a conventional cooling coil, where the refrigerant is first condensed during contact vapor to metal, and the condensate thereafter further cooled.

In practice steps one and two are intimately combined as the following description of some preferred embodiments will show.

From the second heat exchanger step the liquid refrigerant is transferred back to the evaporator 50 by way of a throttling means 57 including capillary tubes.

One embodiment of a condenser according to the invention is shown in FIG. 2 and comprises a cylindrical vessel 1 traversed by a heat exchange tube 6, externally provided with a helically wound cooling fin 5, the radial extension of which is such that the cross section of the vessel will be substantially filled. The vessel is likewise provided with external heat transfer area enlarging means consisting of a helically wound fin 30, which extends outwards about to a casing 12 enclosing the vessel. The casing is, at the end walls 7 and 8 of the vessel connected to a distributor header 9 and a collecting header 10 for the cooling air. A fan 11 is mounted at the exit from the collecting header 10. Heat exchanger tube 6 forms a passage through the vessel, and the two headers communicate by way of the passage and the space between the vessel and the surrounding casing.

The hot vapor arriving from the condenser is transferred into the condenser by way of a conduit, here denoted by 15. This passes through the heat exchange tube 6 and is within the collecting header bent back and possibly split up in branches, passing through end wall 7 of the vessel and protruding a distance into the latter. The portion, or portions, of the vapor supply conduit extending into the vessel is closed at its end, but is provided with a number of axially spaced jet nozzles 21 bringing about a thorough mixing of vapor and liquid. At the end of the vessel remote from the point of introduction of the vapor an outlet conduit 31 is arranged, as well as a thermostat governing the power means driving the fan.

The condenser according to FIG. 2 will operate in the following manner. The hot, compressed vapor is sprayed into the condensate by means of the nozzles 21 and will by direct contact with the condensate practically immediately be transferred into liquid state. The temperature of the condensate is maintained at a suitable level for this function by means of the heat transferring fins 5 and 30, respectively.

The condensate will flow in a helical path towards the exit 31, and will be further cooled during this passage. The thermostat 29 will sense the temperature of the condensate reaching the far end of the vessel and it will in this way be possible to obtain an exact governing of the exit temperature.

It is essential that the distributor nozzles 21 extend sufficiently far into the vessel to guarantee that the vapor is really condensed within the body of condensate and does not rise to the top of the vessel, to form a vapor filled space within the latter. The drawing shows the vessel as operating with its longitudinal axis vertical, but on most occasions the axis will be horizontal, and it is evident that the vapor path then will be satisfactory.

The condenser according to FIGS. 3 and 4 comprises a cylindrical container 1, which by means of an internal wall 2 is subdivided into two compartments 3 and 4, of which the former corresponds to the condenser vessel of FIG. 2. The container is traversed by a number of heat exchanger tubes 6 provided with external area enlarging fins 5. These tubes are sealingly attached to the end walls 7, 8 of the container. This is enclosed in a casing 12, which defines an annular passage outside the container.

An air distribution header 9 is arranged adjacent to end wall 8, and a collecting header 10 is arranged adjacent to end wall 7. The two headers communicate by way of the tubes 6 passing through the container as well as by way of the passage surrounding the same. A fan 11 is mounted at the outlet from the collecting header l0, and a thermostat governing its driving means is fitted adjacent to end wall 8.

A heat exchanger 13 is fitted into the collecting header 10 and comprises a number of parallel, finned tubes, which by way of a distributor 14 are connected to the vapor supply conduit 15. The tubes are connected to a collector 16, which by way of a conduit 17 is connected to a spraying device 18. This includes a narrow chamber 19 defined by the internal wall 2 and a further wall 20 parallel to the first mentioned one. A number of spray nozzles 21 are mounted in the further wall 20 and are directed into compartment 3, which is always substantially filled with condensate.

In order to provide a high rate of contact between the refrigerant and the fins 5 of the heat exchange tubes 6, each tube is surrounded by a guide tube 22. These extend almost to each end wall, leaving an opening 23 and 24, respectively close by each end wall. Opening 23 will serve as a weir for the surplus condensate from compartment 3, and opening 24 will convey condensate, having passed along tube 6, into compartment 4.

It is evident that the guide tubes 22, as well as the heat exchange tubes 6 will have to pass through the intermediate walls 2 and 20, as well as through a third wall 26, to be mentioned herebelow.

An intermediate cooler 25 is formed adjacent to wall 20 by means of a further intermediate wall 26, parallel to the two first mentioned walls 2 and 20. The cooling fluid here consist of refrigerating fluid from the second compartment, which by way of a conduit 27 having throttling means 28 is conveyed to the intermediate cooler, where it is evaporated, the condensate being returned to the system in any suitable manner.

A separate refrigerant, such as air or water, may of course also be used. The nozzles 21 will have to be sufficiently long to extend through this intermediate cooler in order to reach into the compartment 3.

The vaporized refrigerant, which may be Freon, is delivered by the compressor at a pressure of 15 kp/cm and a temperature of C through conduit 15. When passing through the heat exchanger 13 the temperature of the refrigerant is reduced. A slight reduction of the pressure is brought about during the passage through the nozzles 21 and a further reduction of the temperature is brought about by the intermediate cooler 25.

A final and full condensation is brought about within compartment 3 and a quantity of refrigerant corresponding to the newly formed condensate will overflow into guide tube 22, and will be further cooled during the passage along the fins of heat exchange tube 6. The condensate will flow into compartment 4 by way of openings 24. The volume of compartment 4 is selected in such a manner that it, during normal use, will be about half-filled with condensate, thus forming a supply to draw from.

The embodiments shown are examples only, and may not be interpreted as forming any restrictions on the appended claims.

Through the direct condensation of the vapor a reduced volume of the condenser is attained, which means a small volume of refrigerant, small pressure drops, an expedient design for the transfer of heat as well as an easily standardized product. The combination of a separate direct condensing compartment and a separate storage compartment makes it possible to maintain a sufficiently low temperature in the first mentioned compartment to safeguard against possible vaporization as a result of sudden rise in temperature or reduction of pressure.

What we claim is:

1. A condenser for a compressor type refrigerating plant comprising:

a vessel having sidewalls and two end walls for holding a body of condensed refrigerant, said vessel having inlet means and outlet means for maintaining said vessel substantially filled with condensate;

at least one hollow member sealingly fitted into said end walls of said vessel to form a passage for cooling air through said vessel within its sidewalls;

said inlet means including at least one nozzle for injecting vapor state refrigerant opening a sufficient distance from the top portion of said vessel to provide a satisfactory path for the vapor to be transferred into liquid state by direct contact with the body of condensate; and

said vessel forming a part of a larger unit, which is divided into two compartments by means of an internal wall being disposed parallel to said end walls of said vessel, one of said two compartments forming said vessel, said at least one hollow member being enclosed in a guide tube, said member and said guide tube both extending through the internal wall, said guide tube adjacent to each end wall of said vessel having at least one opening for communication with the surrounding compartment, said guide tube thus forming a communication between said two compartments.

2. The condenser according to claim 1, further comprising a distributing header and a collecting header disposed outside the end walls of said vessel, respectively; a fan being disposed in said collecting header; and a first stage heat exchanger being disposed within said collecting header, the vaporized refrigerant being made to pass through said exchanger before entering said condenser vessel.

3. The condenser according to claim 1, further comprising vapor refrigerant introduction means being disposed adjacent to the internal wall and having nozzles directed away therefrom.

4. The condenser according to claim 3, further including an intermediate cooler disposed adjacent to said internal wall, said nozzles being made to pass through said intermediate cooler.

5. The condenser according to claim 1, in which the compartment remote from the compartment into which the refrigerant is introduced comprises a receptacle for the refrigerant.

6. A condenser for a compressor-type refrigerating plant comprising; a vessel having side walls and two end walls for holding a body of condensed refrigerant, said vessel having inlet means and outlet means for maintaining said vessel substantially filled with condensate, said vessel including a number of parallel throughpassages which, outside the end walls of said vessel, communicate with a distributing header and a collecting header, respectively, to form passages for cooling air through said vessel within its side walls; said inlet means including at least one nozzle for injecting vapor state refrigerant opening a sufficient distance from the top portion of said vessel to provide a satisfactory path for the vapor to be transferred into liquid state by direct contact with the body of condensate; and wherein an external casing is provided which encloses said vessel with a clearance, said clearance forming a passage between opposite faces of said casing and said vessel for communication between said distributing and collecting headers. 

1. A condenser for a compressor type refrigerating plant comprising: a vessel having sidewalls and two end walls for holding a body of condensed refrigerant, said vessel having inlet means and outlet means for maintaining said vessel substantially filled with condensate; at least one hollow member sealingly fitted into said end walls of said vessel to form a passage for cooling air through said vessel within its sidewalls; said inlet means including at least one nozzle for injecting vapor state refrigerant opening a sufficient distance from the top portion of said vessel to provide a satisfactory path for the vapor to be transferred into liquid state by direct contact with the body of condensate; and said vessel forming a part of a larger unit, which is divided into two compartments by means of an internal wall being disposed parallel to said end walls of said vessel, one of said two compartments forming said vessel, said at least one hollow member being enclosed in a guide tube, said member and said guide tube both extending through the internal wall, said guide tube adjacent to each end wall of said vessel having at least one opening for communication with the surrounding compartment, said guide tube thus forming a communication between said two compartments.
 2. The condenser according to claim 1, further comprising a distributing header and a collecting header disposed outside the end walls of said vessel, respectively; a fan being disposed in said collecting header; and a first stage heat exchanger being disposed within said collecting header, the vaporized refrigerant being made to pass through said exchanger before entering said condenser vessel.
 3. The condenser according to claim 1, further comprising vapor refrigerant introduction means being disposed adjacent to the internal wall and having nozzles directed away therefrom.
 4. The condenser according to claim 3, further including an intermediate cooler disposed adjacent to said internal wall, said nozzles being made to pass through said intermediate cooler.
 5. The condenser according to claim 1, in which the compartment remote from the compartment into which the refrigerant is introduced comprises a receptacle for the refrigerant.
 6. A condenser for a compressor-type refrigerating plant comprising; a vessel having side walls and two end walls for holding a body of condensed refrigerant, said vessel having inlet means and outlet means for maintaining said vessel substantially filled with condensate, said vessel including a number of parallel through-passages which, outside the end walls of said vessel, communicate with a distributing header and a collecting header, respectively, to form passages for cooling air through said vessel within its side walls; said inlet means including at least one nozzle for injecting vapor state refrigerant opening a sufficient distance from the top portion of said vessel to provide a satisfactory path for the vapor to be transFerred into liquid state by direct contact with the body of condensate; and wherein an external casing is provided which encloses said vessel with a clearance, said clearance forming a passage between opposite faces of said casing and said vessel for communication between said distributing and collecting headers. 